:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface-hover: #1c2333;
  --border: #30363d;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --accent: #58a6ff;
  --accent-hover: #79c0ff;
  --github: #f0883e;
  --hf-yellow: #ffd21e;
  --green: #3fb950;
  --purple: #bc8cff;
  --pink: #f778ba;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 2rem 1rem;
  text-align: center;
}

.header-content h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.subtitle {
  color: var(--text-muted);
  font-size: 1rem;
}

.subtitle a {
  color: var(--accent);
  text-decoration: none;
}

.subtitle a:hover {
  text-decoration: underline;
}

/* Category navigation */
.categories {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  padding: 1.25rem 1rem;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}

.cat-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.2rem;
  border: 1px solid var(--border);
  border-radius: 2rem;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.9rem;
  transition: all 0.2s;
}

.cat-btn:hover {
  border-color: var(--accent);
  color: var(--text);
}

.cat-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.cat-btn .count {
  background: rgba(255,255,255,0.15);
  padding: 0.1rem 0.5rem;
  border-radius: 1rem;
  font-size: 0.8rem;
  font-weight: 600;
}

.cat-btn.active .count {
  background: rgba(255,255,255,0.25);
}

/* Controls */
.controls {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  max-width: 900px;
  margin: 0 auto;
  flex-wrap: wrap;
}

.search-box {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 0.5rem 1rem;
  flex: 1;
  min-width: 200px;
}

.search-box i {
  color: var(--text-muted);
}

.search-box input {
  background: none;
  border: none;
  color: var(--text);
  font-size: 0.95rem;
  outline: none;
  width: 100%;
}

.sort-box {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.sort-box select {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  color: var(--text);
  padding: 0.5rem 0.75rem;
  font-size: 0.9rem;
  cursor: pointer;
}

/* Projects grid */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1rem;
  padding: 1rem;
  max-width: 1400px;
  margin: 0 auto;
}

.loading {
  grid-column: 1 / -1;
  text-align: center;
  color: var(--text-muted);
  padding: 3rem;
  font-size: 1.1rem;
}

.no-results {
  grid-column: 1 / -1;
  text-align: center;
  color: var(--text-muted);
  padding: 3rem;
}

/* Project card */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1.25rem;
  transition: border-color 0.2s, transform 0.15s;
  display: flex;
  flex-direction: column;
}

.card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.card-header {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.card-icon {
  font-size: 1.4rem;
  flex-shrink: 0;
  width: 2rem;
  text-align: center;
}

.card-icon.repo { color: var(--github); }
.card-icon.model { color: var(--purple); }
.card-icon.dataset { color: var(--green); }
.card-icon.space { color: var(--pink); }

.card-title {
  font-size: 1rem;
  font-weight: 600;
  word-break: break-word;
}

.card-title a {
  color: var(--accent);
  text-decoration: none;
}

.card-title a:hover {
  text-decoration: underline;
}

.card-type {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.card-desc {
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-bottom: 0.75rem;
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-meta {
  display: flex;
  gap: 1rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  flex-wrap: wrap;
}

.card-meta span {
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

.card-topics {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-top: 0.5rem;
}

.topic-tag {
  background: rgba(88, 166, 255, 0.1);
  color: var(--accent);
  padding: 0.15rem 0.5rem;
  border-radius: 1rem;
  font-size: 0.75rem;
}

/* Footer */
footer {
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
  margin-top: 2rem;
}

/* Responsive */
@media (max-width: 768px) {
  .header-content h1 {
    font-size: 1.5rem;
  }

  .categories {
    gap: 0.35rem;
    padding: 1rem 0.5rem;
  }

  .cat-btn {
    padding: 0.5rem 0.8rem;
    font-size: 0.8rem;
  }

  .cat-btn span:not(.count) {
    display: none;
  }

  .cat-btn i {
    font-size: 1.1rem;
  }

  .projects-grid {
    grid-template-columns: 1fr;
    padding: 0.75rem;
  }

  .controls {
    flex-direction: column;
    padding: 0.75rem;
  }
}

@media (max-width: 480px) {
  header {
    padding: 1.25rem 0.75rem;
  }

  .header-content h1 {
    font-size: 1.25rem;
  }
}